Don't clear if there's no pixels for current frame
Don't clear if there's no pixels for current frame

omf2097/openomf,gdeda/openomf,omf2097/openomf,pmjdebruijn/openomf,gdeda/openomf,pmjdebruijn/openomf,gdeda/openomf,omf2097/openomf,pmjdebruijn/openomf